@mountainbiker hello, I have many Moser models from circa 1980 to 1990.
The example shown might be a "Sprint" model circa 1984 to 1988. The value depends on the frame tubing, components, and their overall operating condition; aside from the aesthetics which appear to be very good. It would seem to be a mid level model given the OFMEGA Mundial crankset; but other components may help increase or decrease the value accordingly. An original Moser "Sprint" (c. '86/'87 Oria tubing) was fitted with OFMEGA "Mundial" cranks, shifters and derailleurs; Modolo "Corsa" brakes; ITM bar, stem, and seat post; Miche hubs; Everest "Oro" chain and 6 speed freewheel. The Moser "Sprint" model sold for £270 brand new in 1987 so it was an obvious economical model compared to their top models which cost twice as much.
The frame is no earlier than 1984 if the decals are original. The 51.151 arrow design was made after January 1984 when Moser set the one hour record that month. That logo was very evident on many frames (pantographs and decals) so it is obviously not an earlier bike. The drain hole in the bottom bracket shell is another indicator.
If seat post diameter is 27.2mm then the tubing is lighter weight (e.g. Columbus "SL"); a 26.8mm seat post indicates a heavier tubing (e.g. Columbus "Aelle") and a lower value frame.
The market in my area (USA) for a "Sprint" level model in above average and original condition would be €200 to €350. Without anymore knowledge or photos I would value it at €200 - €225. If it needs tires, brake pads, cables, wrap, etc. drop the value by €50 - €100.
You can probably find a higher level bike (frame and components) for about the same price or a little more. Moser made quality bikes using a range of Columbus, Oria, and Falck tubing in the 1980s so knowing tubing grades is important. I have Moser frames with top level Oria and Columbus tubing; but also with lower level Columbus tubing. All the frames are well built.
Jesper