Agree..good to have two. I asked Trezor if both the older and newer ones were compatable and Daria said..
For sure, you can place the seed from the previous model into the new device. Both TREZOR model One and TREZOR T has BIP39 Mnemonic format.
You will be required to choose the number of seed words during the Recovery and there is an option for 24 (the TREZOR model One current standard).
AFAIK since the seed words are entered only on the Model T screen (never the laptop) only 12 words are needed to provide the level of security that required 24 words on the original Trezor. Nice to have the option to use 24 words though: you can buy a Model T and initialize with your current Trezor seed if you want.