Do 511E and 311-90 really have the same basic specs as this seller claims?

What are the chances of this being an authentic pair since there doesn't appear to be a trace of aqua-plas on them?

Vintage Altec Lansing 511-E Horns (pair) w/ 288-16 Dvrs - eBay (item 230395083495 end time Nov-09-09 14:33:59 PST)