I've got Led Zep II and I love it, don't know how early a pressing it is, it says 'Made in UK' and there's a number: K40037 printed on the sleeve, disc and disc label. Does that help?
I love collecting vinyl, you can pick up some fantastic things for less than the price of a CD. I have an utterly beautiful copy of 'Katy Lied' by Steely Dan, which is my favourite record at the moment. It cost me a fiver
. I've never really looked into what any of them are worth though. I've got a half decent copy of 'Help' and a nice copy of 'Blonde on Blonde' which are quite old looking.