I think they are Thetford. Might be able to find your here. If I were you, I would take the seat off and head to Lowes and just find one you like there.
Lightweight, stylish, and durable, Thetford's RV toilets are design to be permanently installed in vehicles and offer the comfort of residential toilets.
We had to replace the toilet seat in our rig, save yourself some $'s, all you need to do is go to Lowe's and get an elongated bowl seat that is slow close. Around $40. They fit perfectly.