I think some American operators could have done it, too. All cases I've seen show clearly-hacked artwork, not factory. See Lariat vs. Wild Wild West for a case where Art Stenholm re-drew the backglass for 5-digit scoring on the add-a-ball version.
On your Snow Queen, was the actual mounting board in the backbox badly hacked so that thousands reels for players 2 and 4 were moved to the left?
.................David Marston