that is a 1989 Merckx Century frame. you can see it as it appeared in the 1989 catalog here:
http://www.velo-pages.com/main.php?g2_itemId=28752
reynolds 653 was a very special tubing. it was a special variant that reynolds made just for eddy merckx for the century model. it's a cross between 753 and 531. the rear triangle is made of 753, and the main tubes are a lightened version of 531 (what reynolds called '531 SL'). it was probably too expensive (like 753 is) and difficult to source or who knows the reason but merckx only offered it one year. then from 1990 onward the century frames were made of columbus tsx.
that bike is in well used condition, but it's complete and those are probably the original parts (except the tri-bars, those were obviously added later). take off the atrocious tri bars and find a period correct stem and handle bar (either TTT or cinelli) and rewrap the bars with cinelli cork wrap. then i'd would say you could get anywhere from $700-1500 for it, just depends. having all the original parts means a lot, especially the c-record parts with the sheriff star hubs and delta brakes.