You got them, in order from Left to Right - Torsten Hallman, Sten Lundin, "The Man" himself Bengt Aberg, Staffan Eveqvist.
The first few "works" HL's were built in the US by Profab, from memory there were only 3 or 5 built. Profab then made a small run of Repilca.
This is one of the Profab HL500's
As you know Stew, I build my Aberg replica back in the early '80's using the rolloing chassis of my 78 Husky.
When I pulled the Yamaha engine out and put the Husky engine back in a few years ago I bought another 1978 Husky frame to rebuild the Aberg on. I have just about everthing I need to build it it up, I just need to find a suitable swingarm and seat, plus the time and a bit or spare money.