I am selling a Polo RL (Blue Label) suit on Ebay, which is made in the US, and is fully canvassed.
Who is the maker? Hickey Freeman?
I can verify Black label suits carry a floating canvas on account of my tailor (who Savile Row outsource to). I had a chalk-stripe Black label reconstructed. I doubt this is horse-hair canvas because he'd have mentioned, he'll know this stuff from his Savile Row clients. Floating canvas enables tailors to easily and accurately perform major alternations. The suit carries internal buttons for silk braces (suspenders US English): a good sign.
Personally the few items of Purple label I have I found over-priced. Polo appears very variable in quality and I still can't figure it. I love Rugbys, antiquated British styles, except they are made in China (only downside IMO).
Blue label is unquestionably high quality (I've a Glen plaid jacket) but I'm uncertain whether it is fixed or floating canvas.
Thin wool suits on a fixed canvas is a nightmare for a tailor to reconstruct and often results in pulls when slim-fitting ... had this trouble with Armani and Boss suit jackets.