measure the current draw... if you are getting <0.9A from it, then you have recieved a true premium grade DRB-9VHP, if you are getting 1.15A+, then you probably have a HP G90, which is still a great lamp, just less efficiant.... both lamps are solid performers... but it's really a bummer that all these lamps are so difficult to distinguish.
we found out (long after this thread was originally created)... that digilight has their own version of the G90... and as of latally, it is hard to come by. Digilight still sells G90s as direct replacemants for their better DRB-9VHP. The highest quality version of their lamp, the DRB-9VHP, draws a mere 0.8A, is very bright and white.... whereas the replacement lamps still found at blackrifles and other dealers, are all going to be run of the mill G&P G90s, which draw 1.2A instead... We had another thread going to compare 9V lamps... I sent an email to digilight and found out that they do in fact have a variation of the G90 that they sell as their premium product, but that it is very new, and all other dealers are probably still selling old stock... (And it would seem, even didilight is still selling old stock to some folks for replacement lamps, the only way to get the high efficiancy model, may be to buy the whole flashlight from them, but even then there are no garantees...)