I piped up awhile back with an opinion on the Leo Bottecchia, so @
cudak888 asked me to back up that seemingly authoritarian claim
My story is I've been a fan of these for awhile. I own a 1969 Special, a 1972 Giro D'Italia, a NOS 1989 Equipe with C-Record, and an early 1950's Tipo Giro D'Italia (Tipo or "model" was a common prefix used by Italia manufacturers pre bike boom). The first three were easy to date, especially because I purchased the Special new. The older one is my estimate (1950-1954) based on the components that were on it when I acquired it, and the fact that I have yet to see any Bottecchia made after 1955 with these particular head lugs (see Flickr album link below). Now, back when ebay was a relatively new thing, I was fortunate enough to invest around the IPO - so I was watching the company and the auctions for bikes closely. In those early years there were three outstanding Bottecchia items that came up that I noticed. I was able to purchase one of the three. The other two were late 1950's complete bikes, one original and one restored. Had I been smart, I would have archived those photos. One that was claimed to be a 1959 Giro D'Italia had a seat tube very similar to my old one (chromed panel with decal) and lugs very similar to the Leo. I also recall seeing similar lugs in a couple of models claimed to be early 1960s. Once the bike boom Bottecchia's started to show up in the US, we don't see that style of lug to my knowledge - but many other carryovers did come along like half chromed stays and chromed head tube lugs. Hence - my claim that the Leo style looks to be somewhere between 1955 and start of the bike boom.
Flickr album of early 50s Tipo Giro D'Italia:
https://flic.kr/s/aHsmETCHxd