I mean, it says "Eddy Merckx Custom" on the tubing sticker. Did most bikes of the period get that (as it it was a custom set of butted tubes that EM got - I've heard that he got MXL tubing made because he didn't like the look of the oversized top tube in MAX, but it was otherwise the same), or does it mean that it was tubing used by Merckx for custom builds (I haven't heard of them doing that, but maybe they had a special wing of the shop for really high end customers who could pay for custom geometries).