A side view would be better but it looks like a ball valve (1/4 turn) not a gate valve.
But who cares? Getting a new valve in and out without breaking anything is what you need to worry about.
New valves are cheap.
Side view as requested. Sorry for the image quality. The valves sit down in a sump in the laundry room next to the boiler, making it a little difficult to get a good side view.
My wife was worried about how the pictures looked - I tried to explain that the plumbing was 60 years old, and wasn't expected to be chrome plated and sterile. At least, I wasn't expecting it to be. I guess I'll be steam cleaning and plating the stuff on my next days off. ;-)
And since she's reading this over my shoulder...I love you honey!!