Anyone can market anything,
but for it to be legal in any specific country it must correspond to ALL the laws of that country.
Here in the UK an air "rifle" with a folding stock that can be fired single handed,
as a pistol, with no shoulder stock is illegal if over 6fpe, because of the pistol bit.
A prime example of the legal requirement is the Hatsan AT-P2, with the stock fitted it could be a "carbine" but because the stock is removable to make it useable in "pistol" format it was limited to 6fpe.
A "rifle" is a shoulder fired weapon.
There is no such thing as a "section 1" air pistol over 6fpe, in the manner of LBP/LBR, if it's over 6fpe & can be shot as a pistol, under UK law it becomes a section 5 prohibited weapon.