TanaMa
My father, when spotting girls/women dressed in too short/too tight clothes, always said 'the sights you see when you haven't got your gun'!! Probably wouldn't be allowed today!!??
In my twenties , in the 1970s , a Scottish friend of mine (Glaswegian actually) , who was female, introduced me to this phrase so I had always assumed that it was Scottish in origin. She used it generally of anyone or anything of odd appearance. We also went out dancing together "on the pull" and then it wasn't used only of unappealing women.........
Possibly it was handed down by military men in her extended family.......