I loved POTCO. I started playing early in its life, but only really started playing between 2010-2012. I was only 10 when I started playing for real and I didn't have the mindset or skill to get really deep into the game. So when it was closed in 2013, I was sufficiently upset, but I didn't try and see if it was being remade until 2015.
At that point I believe TLOPO was only open to key testers and a little later the devs added a time slot system. I got myself a time slot and noticed there was only fishing and potions.
I knew progress had been made, and more progress would be made, but that was the last time I played Alpha. I didn't know obtaining a key was easy, or that you could even dig for them (correct me if this is wrong). That's why I didn't get upwards of 30 keys like others have said.
So, I guess rewarding the more dedicated players are fine, but giving them a founder tag is a little bit much. Maybe make it a "Tester" tag instead. Like others were proposing before elsewhere, use email to see whether or not you played alpha or semi-open beta if possible and then those people get an "alpha tester" or "beta tester" tag.
I know right now that would be the majority of the players, but I feel anybody who was at least dedicated enough to play using time slots in alpha and queue times in beta should not be left out.
That's just me.