As I haven't a copy, yet - how are things broken down? Do they actually have Mechs by era, like with TR '39?
One of the things I've usually maintained is that it isn't difficult to allow players to play in any era with intro-tech designs. That should be a minor goal of the devs, which seems to be the case.
Shoot, some of the 'advanced tech' like ER beam weapons don't have any special rules to worry about, and can also be incorporated in boosting the introtech player's arsenal.
A lot of these mechs are still playable across all eras, though many of them might not be as competitive in some.
Maybe we are overthinking it, as usual.
I would normally disagree on that, but since the product is already out, it's really down to head-games. ^-^