Factory Replacement (?) Cannondale CAAD3
 

I have a bit of a mystery bike. It is a Cannondale CAAD3 with no model name written on the side but stamped 98 on the bottom.

https://cimg8.ibsrv.net/gimg/bikefor...6bc4f3ac7.jpeg
https://cimg9.ibsrv.net/gimg/bikefor...189f7b774.jpeg
https://cimg0.ibsrv.net/gimg/bikefor...893e079ba.jpeg

It appears to be a mix between the 1997 R800 (CAAD 3)

https://cimg4.ibsrv.net/gimg/bikefor...ca56995fa.jpeg
1997 R800 (CAAD3)

And the 1998 R300 (CAAD2) paint scheme


https://cimg9.ibsrv.net/gimg/bikefor...48f4a8e05.jpeg
1998 R300 (CAAD2)

Is it possible that this is a replacement frame and Cannondale no longer had the yellow paint from 1997 model line for the Viper Red fade to Speed Yellow (YVR) and chose to paint the frame with the 1998 model line Blaze Red Fade (BLZ)?

I'd go with the group to determine model. You can ask here...
https://www.bikeforums.net/classic-v...annondale.html

Thanks, I'll check that out. The group on there now is not original, I got the bike from a retired triathlete and I think he swapped out the original for a Shimano 600 set

I have a similar ~99 Cannondale (an MTB Super V), in that it has no model number on it despite being the original factory paintjob, the reason being.... it was purchased as a frameset from the dealer and built to customer spec.
I know this as the guy I bought it off was the shop owner (A 'Dale dealer) who sold it to the original owner, who then PX'd it back to the shop several years later, he told me that often frames were available to dealers this way but not advertised in the catalogues, whether they were supposed to be sold like this or whether they were pulled from spare warranty replacement stock I couldn't say.

So could yours be similar, a frameset that was purchased and built up rather than an off the peg?