If you have the frames in your possession, then take a bunch of photos including photos of the tops of all the lugs and the bottom of the bottom bracket. Also can you discern any branding on the dropouts (fork and rear)?
Can you make a hand drawing of the shape of each of the tubes to the best of your ability?
Like @
francophile and @
Drillium Dude, I am extremely skeptical that either bike is actually a Colnago. And, I am also concerned about a possible bent head tube on the purple bike.
I'm having difficulties discerning the tubing shapes that you mentioned. However, while Colnago was one of the major manufactures using shaped tubes, they weren't the only one.
Stuff that says
"Not Colnago" to me:
- Pump Nipple. I don't believe Colnago used them on their bikes. Certainly not a common feature.
- Non Colnago Fork. While some of the early ones weren't branded, those all had flat fork crowns. Yours is a later design, and if it was Colnago, it should be branded.
- I can't discern any clover cutouts or pantographs, or Colnago script on any part. Common locations would include:
* Top of the main tube lugs. (a couple of lugs appear to be visible on the red bike without the cutouts).
* Dropouts should be either "Colnago" or "Campagnolo"
* Square brake bridges usually have a clover.
* Fork Crown Markings. "C", "Colnago", Clovers, etc.
* Bottom of bottom bracket.
* Seat Stay Caps
- Also note the rounded seat stay caps (red bike). These are a relatively later introduction, but I believe almost all have the clover pantograph. Other models had the "Colnago script". Very early models had a concave seatstay cap, without markings. But, that isn't your bike.
- No script visible on chainstays.
- Brazing the seat stays and chainstays to the rear dropouts, Colnago tends to use a very crisp concave half-round connection. Yours seems to have either a simple taper or a simple flat overlap.
More photos and diagrams of the tubing shapes for each main tube will help confirm, but at the moment, I'm leaning towards fakes.