The top medal on this page:
http://www.theeasterrising.eu/140RoyalVisits/RV.htm
is the one usually attributed to Parkes. Count the shamrocks, there's a different number.
A large variety of medallions were issued, only 4 or 5 officially, and the literature is sketchy. The official issues are listed in Lawrence Brown's British Historical Medals Volume 2. The BHM numbers start around the BHM 1130 mark.