If you bought Sam and Max Save the World (season one) from the Telltale Games store back in the day, you are now eligible for either a Steam or GOG key to transfer your game. Just go to the appropriate link on the Skunkape website. Cool thing: "It’s okay if the email doesn’t work anymore; this step is only for verification."
You'll want to acquire it ASAP, as having the key in your library makes you eligible for a 50% discount for the remastered version through December 31, 2020.
Instructions: scroll down to the section titled Telltale Store Customers, enter your email, and choose the store you'd like, which it asks about after verifying. Once you have the original game in your library, go to the Sam and Max Save the World: Remastered page (GOG, Steam) and get the discount while it's valid. I've just tried it.
Mojo will give you a heads-up (timeliness guaranteed*) if news of the same comes out regarding the other two seasons. In the meantime, get to updatin'.
Sam and Max Save the World: Remastered releases for PC and Nintendo Switch December 2nd. (It's not the official title, but let's pretend it is for the sake of clarity.)
*Timeliness not guaranteed.