Looking at the the from address in an email is safe.... although spoofing an SMTP address is piss easy so not the best proof of fake/real.
In this day and age.. Don't click it anyway. There are a couple of ways to make at least obscure what's happening.
My experience is not so much about scamming as well as people selling stuff as something more expensive.
I tried out a 2nd hand les paul that was supposedly a $1500 plus model. I had my doubts going in. If the guitar was a couple of years newer then stated it'd be an $800 axe.
So I drove over, tried it... And well there's no way that was the $1500 model. It wasn't a bad guitar at all but not worth the $700 the guy was asking.
Now he got the guitar from his parents or a friend or something like that. He honestly didn't seem to know better. But especially if you're a less experienced player it's easy to spend too much money.
If that had've been my second guitar I probably would've bought it because it would've been a truckload better then my first guitar.
The lesson here.. If it's too good to be true, it probably is, check serials.. And if in doubt.. don't do it.
I'm sure there are good deals out there.. But you're not going to get something for half of what it's worth anymore.