Just emailed friend a pic of this truck, he says it a 49...Hope this helps..

Looks like it could be a 47 , the 48 looks almost the same but ornament on the rad shell is different...Try this like it is a link for the Diamond T truck...http://www.diamondtclassics.com/modules.php?op=modload&name=XForum&file=viewthread&tid=2764#pid....Good Luck...