A light gun/pen requires a CRT but it does not necessarily require a raster display. There are various different ways to find what the gun/pen is aimed at, counting the position on the screen raster is just one of them.
I have made 8 high-score saving enabled cartridge versions of some of the original Vectrex releases.
Available as sets or individually from my ebay shop : https://www.ebay.co.uk/usr/kq_76
I have made a few hacks of older games (Star Hawk and Patriots 1/Remix/3) to allow the use of Atari CX-80 or CX-22 trackball.
The hacks can be downloaded from my website : www.binarystarsoftware.com/?page_id=460
A compilation of some videogame music I converted from the Amstrad CPC (which shares the same sound chip as Vectrex) :
Download : binarystarsoftware.com/bin/YMusic_v100.BIN