I had written a long text which I lost due to bad internet connection, so here the short form:
I highly doubt those are RM 2000 RTP.
1) If they are RTP, you need to own RM 2000 the be even allowed to use them - and then you wouldn't have to ask.
2) In the linked post three sprites of different quality can be seen. They are definitly not by the same author or there is quite a time of practise between them. The "cat" (I think it's a dog) could be by Mack, but I have no ideas about the creators of panda and crocodile.
3) In the linked post you see a database full of animal sprites with the same naming system. It was very pupolar to collect resources of one type (here: animal sprites) and make huge download files so everybody could easily get them. Downside it that this breaks the terms of most of the original artists and all credits are lost.
There are two safe to use crocodiles that come to my mind:
whtdragon's and Peter-Calcifer's