"Matched" sets are overrated and overpriced... any random pair of like model CPUs will have the same performance as whatever a "matched" set brings to the table.
Did a quick search on Ebay...
https://www.ebay.com/itm/LOT-OF-2-I...6UAAOSwLJ9Z7hnc:sc:USPSFirstClass!19709!US!-1
I've used this seller several times and never had an issue.
For X5365, matched pair is actually required. You CANNOT pair up a X5365 SLAC3 (B3) with a X5365 SLAED (G0)