I've been puzzling hard over this classic Rogue Trader Medic recently.

Rogue Trader Medic

Released in June 1988, he comes armed with a lasgun.  When the Medics were codified into the White Dwarf 109 (January 1989) Imperial Guard army list they had no option to upgrade their default laspistol to a lasgun.

So, how can you field this model using the White Dwarf 109 army list?

Sod it, just use a different Medic miniature?  Ask the GM for a roll on the standard weapons chart for a cost of 3 points?  Sub the weapons with the charts in the main Rogue Trader book (as had been the case with the earlier Imperial Guard list in the Book of the Astronomican)?  Just play counts as?