I've got 2 of these. Greedy I know but I started over 50 years ago with a Johnson and Johnson contact printing frame for 127 film, and only finally got to this sort of gear 3 years ago, just before I retired. Any way I bought them on eBay attached to a Focomat 11c and a Durst DA900, one of the 500ss packed up and I got a replacement from eBay USA. To cut a long story short, neither is a 2nd generation model ie no heat shield blinkers or whatever they are; I know what you mean I've seen pictures. But, they both came with 300 w ELH bulbs fitted, so I am not sure the upgrade from 150 to 300 came with the fitting of blinkers; it may have come earlier. Or, when it came, users decided to fit the 300w bulbs anyway
HST, I do find that despite the fans onto the bulbs down the flexible piping, there is a lot of heat; even 35mm film 'pops' within seconds of lighting up, so I use perforce double glass neg carriers. Might be able to get away with upper AN glass, glassless below - haven't tried yet.
Richard