Andy,
I am aware of a World Championship in Track won on a Paramount in 1976 or so (Matt Assenmacher has the bike it was won on hanging on his wall is how I know of this). I am sure Schwinn would not fudge on this, but I can't recall anything from 1973. I have Paramounts from 1972 that do not have the stripes and I had a Team Schwinn Paramount Track bike (Now in the List Meister's clutches) from 1975 that I don't think had them.
Do you know what Paramount won in 1973 that might induce Schwinn to add them that year as on your bike?
Thanks,
Tom Sanders
Lansing, Mi USA