Signature seat stay caps indicate a very early and quite rare Merckx Professional. I am looking forward to seeing pictures. Mine has Mavic tubulars mounted. A tied and soldered gray anodized 32 hole GP4 on the rear and a gray anodized 32 hole Special Service Des Courses on the front. I believe the bike was raced early on. The GP4's would be appropriate, but many don't like the trouble and expense of running tubulars. Lots of threads here about that.

And the bike almost certainly originally carried Record hubs.