Defunkd

[ThreadbareTees]

For this shirt in particular it won't make any difference.
The copyright is not the same as when it was made but most people would be able to date yours and the other one for sale on Etsy to the same time period by looking at the tag.
Don't think people really care what wording is on the print as long as they can tell (or are told) it's legit.

I think in general it doesn't make much of a difference at all.
I've sold lots of band shirts and the copyright wording and tags are often different here in Australia to what they are in the rest of the world but most things are still worth pretty much the same price.

What you'll notice when trying to valuate a vintage t-shirt is that people will just pay different prices for things. There's no exact value for anything second hand. More so just a range.
I've been selling vintage for 15+ years and some people are more than happy to pay your top dollar, others will abuse you when you tell them your absolute bottom dollar.