The Reynolds 531 label would be on the seat tube, or possibly the downtube. But looking at the steel rims, kickstand and cheap components, it's likely a hi-ten frame, not 531. The fork is, in all likelihood, not chrome-moly.
I have a similar bike in blue, with the same internal brake cable routing and some cool 1970-ish graphics. It's heavy and has cheap controls, but I got it on the cheap and don't really care about the value; to me it's a conversation piece, little nugget of the time.