Put the $450 aside as a contingency for about a month. You're probably out of the woods but better safe than sorry.
And of course if he does contact you after the time is up, you have a moral issue to deal with.
XL5: Home of the "smarty pants" comments. Want: 2010 Allen & Ginter N43 relics of Pujols, Markakis, Howard. Want: Konerko high-end, looking for any Konerko 2012 Topps Series 1 & Topps Chrome 1/1s