Its not a canon picture, but it is very close with the exception of the mars pattern lasgun (which are supposed to look like the old Imperial guard ones- that metal tallarn, Praetorians and Mordians still use...
I think Dan Abnett put in the different sized lasgun power packs into the Gaunts Ghosts series first- and as a device to increase problems/tension and relate with reallife war situations.
However since then Lasguns look like anything. The Inquisitor rulebook expanded on it after the plastic catachan mopdels were released (giving us Galaxy and Voss patterns in that wave of releases). "Kantrael" is what the cadian plastics use. All the rest are Forge world models. Thay have missed dout the Vostroyans though.