I have seen the covered pews before, and the ones I saw were solid Oak. I'd think it was all about what was paid for them initially. Some Church build drives amass a huge amount of coin. Maybe try to ask if anyone was around when this church went up. I will say that the Church I saw the pews available in, it has massive Oak beams, and this Church has what look like basement posts, so possibly a low budget affair.
Call and ask, no cost, and very little time in doing that.