Hard to know, but it is probably only product references. One way to check would be a pattern, like the same first numbers for two devices. If it is indeed serials, the only way that could impact you is if someone could somehow go to RSA and check if they have records of matching ids and private seeds. So, unlikely to happen.
You could also think that the private seed in the SecureID was used to produce the serials: how much of the seed would it reveal? According to this (might be a different device, same company), the seed is 64bits long. How many bits could be encoded in you serial, and how much would that reduce the security of the algorithm? (e.g. it needs 20 base-10 characters to encode any 64bits seed).