If his were 'very old', it's quite likely they were cast - as Ping only started producing forged irons/wedges in 2011 or 2012!
Even forged wedges have different feel attributes - metal, finish, hosel length and a host of other things can affect feel! Vega and other Kyoei base forgings feel 'brighter' (cast-ish) than the likes of Miuras - which seem to me to use Vokeys as a 'model'.
I have a pair of Vokeys (cast) and an equivalent pair of (forged) Clevelands. They feel almost identical to me - and I'm quite sensitive to 'feel'!
You could ask the guy why so many tour players use (cast) Vokey wedges even when they are sponsored by other brands! Btw. Vokey does make forged wedges, but that is almost exclusively for the Japanese market, where cast is considered 'cheap' - so not as good !