How do you complete an "incomplete cart" from Steve's Carts?

[Kommunističeskiĭ]

I "noobed out" while trying to learn how Steve's Carts works, and I ended up with two "incomplete carts" because I broke the cart assembler before completing the cart. I did this in a survival server and I spent quite a bit of resources on the carts. Is there any way to complete them? Thanks in advance.

[Kiwionrails]

Have you tried sticking them back into an assembler and giving it fuel etc to complete the cycle? (I'll add that I haven't played with it at all, so don't know if you can)