Looks like San Pedro very much - but it also looks like someone knows what they
are doing: multiple cacti are growing from one spot, so someone must have
planted a cutting horizontally. Also they do look pretty healthy to me (to be
honest, my San Pedros look less steady, but that's probably because I'm having a
little trouble with getting them enough sunlight).
I mean you can always try to buy them, maybe the old couple will then grin, say
no, but invite you to trip with them (remember the old '68 generation is in their
60ies today, so your old couple might as well be old hippies!)
But I agree that almost nobody knows San Pedro cacti. I have a couple of them
on my balcony, there's like 20 neighbours who can see them, I never hide
them when I have visitors, no matter who. The most they do is say: oh you
seem to like cacti!
And I say, yeah, you know, these are the only plants I can grow because I
always forget to water them, but cacti don't mind. It's really fun to grow
them in the open and nobody suspects a thing 8)