Originally Posted by USAZorro
If it is stamped - it certainly is not a high quality frame. If it does not have a separate hole for a derailleur to attach to, it almost certainly is not a high quality frame.
You can't always judge quality this way though... Lots of older frames with nice lugs and quality tubing didn't use forged Campagnolo, Zeus, Simplex, Huret, etc. Drop-outs with derailleur hangers.... You have to take a closer look. Two examples I can think of right off, are my 52 Hetchins Experto, which uses Chater-Lea drops (no hanger- originally set up for either an Osgear or a Sturmey rear), and my '76 Jack Taylor "clubman" (fillet brazed 531, and STAMPED Campagnolo drop-outs - no hanger). Again, you need to take a closer look to determine quality (and I still don't always know what the heck I'm looking at...) A recent bike I bought at a thrift store was overlooked by folks thinking it was another junky Schwinn, like a Varsity or Continental... While it was another junky Schwinn, it was a fillet-brazed Super Sport, that looked like a lesser model, but it was made of much better tubing. Stare at potential buys for a while... You may see more than you did at first.