Unfortunately, this is not possible – each deployment is a discrete operation that has no awareness of the others, so it is quite possible for the same custom computer name to be generated twice, particularly if you’re only using two pseudo-random digits as you’ve described below. You can significantly reduce the likelihood of identical computer names by increasing the number of random digits (this is why we have 8 digits by default), but the only 100% reliable method is to use a non-random method of computer naming – either reading from a wmi query (this can include the user-definable Asset-tag field, which is available in the BIOS on many devices), or re-using the existing computer name.