Nay, its not sure at all, they can have heat several days after a succesfull mating too, and thus - they can and do mate several times...
@StefanZ I know they were mating. I just really hope it didn't stick. The vets near me will not spa her until the babies are 8 weeks. I am really trying to make sure noting happens between the two. I do not want her to have more babies. Since today she tried to get someone to mate with her, does that mean the mating yesterday didn't take?
If you kNOW she mated, the probability is high it took... I would recommend spaying, if you dont want to have another litter in 65 days. The question is only, if you do it asap you can arrange it, or wait a couple of weeks. I presume you dont want to spay when she is high preg. Very few people wants it, not me either.