EVERYthing is easily forged these days. ask a PO clerk how many counterfeit US postal money orders they see come thru regularly. the only safe bet? take any form of payment and hold it till it clears. as noted banks and even different clerks in banks will give you different lengths of time from over night to 10 days. now that the 5 clearning house banks are all electronically linked 2-3 days is plenty of time. 10 days is what it used be when everything was snailmailed around.
most expensive one i've taken was $1200 in postal money orders and i asked the PO to verify that they were legit. they can look up the # and tell it's one of theirs. cheaper stuff i alwas put in ads that payment will be held as bank recommends to clear. then if everything looks OK i go ahead and ship anyway. i figure anybody with good feedback ain't gonna risk it over a bad $25 check and no one but a complete idiot would send bad payment knowing up front it would be held till it had time to bounce.
but again - that's cheap stuff. wait till it clears and assume NO FORM OF PAYMENT is beyond faking.
i had an ebay guy chew me out royally once over a money order from some gas station in washington state because i was going to wait for it to clear. tough. read the ad.
roger