It has now been established that the Generation 1 frames were just that; there were no limited editions and they were manufactured between late 1974 and c.1976.
There were Generation I frames and later Generation 2 frames. The quality of the frame was not denoted by the [number of] parallel cut-outs on the underside of the bottom bracket, the only guide as to the quality was the Columbus tube sets used, generally SL or the lighter Record.
It seems that these Generation 1 frames were initially numbered; stamped on the underside of the bottom bracket, when the numbering stopped is not known. The Columbus Record tube set frames were produced for time trials and they had different head and seat angles.
Generation 2 frames had the bottom bracket cut-out in the form of the revised R, which was introduced after the legal matters had been resolved. This R was more compact and "chubbier" than the original R and can easily be identified by the "blob" on the end of the bottom right-hand leg of the R. All Rossin decals from this time onwards had the chubby / blobby R.
The Generation 1 decals had the wider R with a longer top left lead-in and a longer right-hand leg. My attached photograph shows the original Generation 1 decal design.
There are other distinguishing features which apply to these early Generation 1 and Generation 2 Rossin frames.
