I have a 1983 Trek 520 that has no braze-ons for downtube shifters. When I got the bike it had Suntour barcons and a downtube clamp for a cable stop.

Just about every picture I can find on the interwebs of this bike include downtube shifters. Vintage Trek lists the serial number as a 1983 Trek 520 so I don't think I am crazy...or am I?