really the slab doesn't even look real... http://cgi.ebay.com/1928-Wheat-Cent...240:1318|301:0|293:12|294:50#ebayphotohosting
It looks like a sample slab by PCGS. There is a post somewhere around here that shows the different slabs...
That is a real slab Just an older one... It is a sample slab, used by PCGS, and byrd has given the right link to go to