Help with identifying, Opuntia monacantha?

The church opshop in our little town allows people to drop off plants they don't want, as long as they're in "decent" condition, and they resell them. I saw this as I was walking by and it caught my eye. Actually, as it was sitting on the counter when I was buying it, someone else asked if they could have it. It's in a bit of a sorry state but I wager with a bit of cutting back and some TLC there's hope for him. I'm thinking it's an Opuntia monacantha (drooping prickly pear) but in its sorry state I'm not 100% sure. Any help is appreciated!