Yes it is, as to be sold in the UK IT HAS TO BE MARKED NOT FOR USE ON UK ROADS / STRICTLY OFFROAD USE ONLY. Unless it was sold with headlight washers and sefl leveling retro fit kit which some kits are ( close to 950 quid ) such as the Valeo one.
Also if you buy an airgun, well completly different ball game, we're talking about non-road legal car parts. Maybe compare it to bike race exhausts