Is this guitar a good deal (1970s Greco)?

If it's in good condition that's a great deal.

There were a few Japanese companies making these copies. Tokai is probably the most sought after. They made different models at different price points. So some are higher quality than others.

The models made in the late seventies to around 1985 when the Japanese companies were forced to change their practices by a lawsuit have a reputation for being quality instruments, and as I said previously there are examples that are as good or better than some of the originals they were copies of.

If that guitar is in good shape, stays in tune, and you like the way it sounds and feels, then it is a steal at 250. Especially with a hard case included.

I know a good deal about Grecos. I play an 80's model SA-64-70. One of my jam partners plays an 70's model SA700.

The real sweet spot for the Greco semi hollows is the mid/late 70's / early 80's. Check out the listings on eBay. Keep in mind that the earlier models (60's early 70's) are a bit hit or miss. Same with the later ones once they moved shop to Korea.

For that price, I would be tempted. But just know that no vintage ES-335 style guitar is not without its own "problems". You'll have to work that out on your own. The price on what you have listed, I would be willing to spend that amount and take it to my luthier.

Make sure you ask the right questions. How is the neck? How is the binding? Any cracks? Any buzz?

In short, the price is very very tempting, but you are also very right in questioning if it is too good to be true.

ETA: Honestly, I would be wary. Do your research. Know what you're getting into with a ES-335. It might be easier to transition to something like a vintage American made Fender Telecaster, depending on what sound you're looking for.

Good luck!