I've never asked myself this question, I guess most grandmas are on the old side but at the same time I consider the landlady still quite young, if we consider the landlady to have less than 40 years old I could understand the grandma being between 55 and 60 if not less (maybe even 52 = 18+18+16)How old is "grandma"?
I won't vote since I don't like old and end up holding CTRL through any unskippable content. But, in terms of realism... if she's 65+, I'd stick with original. If she's 50+, you could get away with NM-GRAY1.
New Model looks like she's around the same age as his mom, if not younger.