I'd value a Serotta in good condition, fully built, and the right size for you, much more than $300. I traded a poorly painted 86 Serotta with Campagnolo for a bike I had on sale for about $250 and considered it the deal of the year. Frame does not appear to be lugged, but the white color may be making that difficult to make out. Appears to be early late 80's but more likely early 90's, just before or right during the time STI came on the scene since it still has downtube shifters. If I were selling that bike, I'd ask for not a penny under $600.