Hopefully this one hasn’t been covered already, and appreciate your input. This Eddy Merckx frame has been listed on eBay for quite a while, first as a complete bike and now as a frameset. I was wondering if you could determine if this was a Reynolds 753 frame. The seat stay treatment looks like what I’m used to seeing on the 753 frames, internal rear brake cable routing, number tab, Eddy Merckx brake bridge and Corsa Extra style fork crown.
Bottom bracket:
Left Y 5
Right A 6382

Seller lists as a 54, but guessing it’s a 55.