I also have aSimpson 260, one that is rather unusual in that it comes with a "roll top" cover.

Fair Radio Sales Co sells a number of different type test leads.  They may not be original to the  260 but at least some are real test leads.  By the way, the biggest problem I have found with those cheap digtal VOMs they sell at Harbor Freight is that the test leads are rather fragile and irrepairable once the wire breaks off the probes.  And a set of good test leads will cost you as much as the meter.
 
Wayne
WB5WSV