Where should I send for repairs?

So my last post was on my father’s 1960 Superposed. I took it out hunting and for pheasant and some skeet shooting, she did great! I did notice however that the barrel length sighting on the over barrel is just ever so slightly separating. I took some photos and it’s tough to see. I discovered this because a brownish color oil substance seeped out from under the sight after 4 rounds of skeet. I should have took pictures before wiping it but oh well. My question is where can I send the barrels to to have the sight be properly repaired? It’s in great condition and I don’t want to trust it to just anybody.

That's a really nice heirloom piece.
Given its sentimental value to you and looks very tidy, do plenty of research and educate yourself in exactly what's involved in re laying a rib and side ribs before you commit to anything. It won't be cheap repair and time consuming.
Go look on Shotgunworld in Browning section and there is lots of posts etc there worth reading.
There is lots involved in setting up and doing this repair properly and accurately, including rust bluing the barrel again after the repair.
Just giving over to the first hack you find that puts their hand up could be a very unhappy outcome and result in not shooting to point of impact or having to get re done.
I have done this job few times myself so I know exactly what's involved in getting it right.
Hope this is helpful guidance as it is a nice piece and deserves the correct attention and it will go another 60 years.

Do you have contact info for Art’s gun shop? Does model west Gun Works do repairs as well as sell parts? Thank you

thank you for the kind words! Fortunately the rib is still good. Just two portions of the sigt rail near the end of the barrel. I’m sure that’s also quite a job but like you said it is an heirloom for my family and I’m pretty good shape. I appreciate the insight.

I’m sorry if I don’t know the vernacular. I re read your post and realize you talked about side ribs and guessing the top rib would be the sight rail I spoke of.

No your all good.
Check close visually along the side ribs (triangular section that runs full length sides between barrels) they are soldered too.
While barrels are off and flat supported on a bench Press your thumb real hard along each side or use screw driver pressing into little bit of scrap wood to stop any marks with some pushdown at 1" intervals and look for any sign of oil squeeze out. Use a magnifier if necessary.
If top rib has lifted as your saying it's likely the soft solder is aged and failing in this region as well. It just naturally work hardens with age and barrel flex resonance every time a shot is fired.
They will have to unpick all this anyway to do job properly.
Now you have some ideas and arm yourself with questions from research to ask of a repairer.
Good luck in your quest

Thank you! I will check on this as well. I’m sure it is not a cheap fix but it is completely worth doing!

So you would trust them with a repair like this?

Always a good idea when shipping something expensive to someone unknown, even if they are highly recommended.

If it was me I would be inclined to look around a bit. Unfortunately I am too far south like 10 000 miles to know who's who in the zoo for US.

This type of repair requirement is not uncommon on the older superposed manufactured right up to later 60"s when they switched to using silver solder and induction heating instead of the traditional sweated soft solder.
You may find an older school gunsmiths out there who is very familiar, really experienced and neat with the process.
I would ring Scotties gun works in Tn or Ernest Marlett in Ga just to get some ideas. Or leads . They will tell you what they think makes a good job and compare to what Art tells you.
You don't want a half ass job as it means something being an heirloom.
A half ass repairer will tell you they can just re do the section that has lifted and save you some money. It will ultimately fail later.
A craftsman will tell you how he is going to go about it the right way and do it once and do your heirloom justice so you can shoot it hand it on to somebody yourself.
Report back some time how you get on.

I echo Aussie's comments, above. The gun has been re-blued as evidenced by over-polishing and rounding of corners (like the barrel lugs shown in your previous thread "Looking for help identifying") and 'bluing' of surfaces that are typically 'white' metal from the factory or otherwise, from a proper re-finish. The current rib failure could very-well be the result of that work relative to type of solder and method of re-bluing.

Good luck