is this the real deal?

Looks good to me. I've yet to see a fake from the pre-NFL equipment era - ie with that smaller shield on the neck. If someone had gone to the trouble of making a fake one, they'd pretend it was a Mitchell and Ness and that its worth over $300.

In fact I am wearing a Jerry Rice one from that era currently. The tag in the collar is the same, as is the jocktag on the front. I'm not sure why the stitching from the letters on the back go through to the tag in the collar though. My Rice doesn't do that, but it looks like that one there had its numbers put on by a different company - hence that second jocktag. I'm also not sure whether that 50th patch is an original or if somebody has sewn it on later. Perhaps some 49ers fan knows?

I agree, it looks ok to me. I would think that the nameplate has been added later and whoever did it was lazy and didn't take it off before stitching on the letters I can't tell if the patch is real or not from the photo.

On the whole though it's a pretty cool jersey.