I have a couple dozen sheets of very old (bought in 2004) Ilford Multigrade IV RC Deluxe (MGD.1M Glossy) paper. It's 5x7, and I'm going to expose it in a 5x7 pinhole camera. I'll develop a part of an unexposed sheet tomorrow to see how badly fogged it is. If it is fogged, will it still need to be pre-flashed?

Also, how should this paper be rated?