Generally speaking, "bail" on a traffic ticket is just a way of saying that you have to pay the ticket, even if you intend to fight it. The idea is that if you are found not guilty, you will get the money refunded, but you have to pay it up front to get the hearing. Sometimes, expired registration is not a "fix it" ticket, but just a ticket. You should check to see if the citation indicates that you can get it dismissed by correcting the problem.
If it is just a fix-it ticket, and there are no more serious criminal charges related to this incident, you can probably address this question directly to the court clerk for the courthouse that would hear the case. They may accept proof of you fixing the registration, set a hearing date, or at least be able to explain the issue to you. Bring proof of your registration. If for any reason there is the potential of more serious criminal charges connected with this fix-it ticket, then you should definitely contact an attorney before talking to anybody about this case, including the court clerk.
We do not have a client/attorney relationship until you make an appointment, we discuss your case face to face, and a judge appoints my office to represent you in your criminal case. I am not available at this time as a retained private attorney and can only assist persons in the process of applying for the services of the Public Advocate.