You should try it. I did and that was the reason I start designing with Z80. I bought a lot of 10 for $9.90 and need to come up with a design to run them at 20MHz and beyond. That with the beginning of Z80SBC64. 9 out of 10 worked, I can't believe it and bought another lot, 10 out of 10 worked. By worked, I mean passed
zexall.com at 22MHz or higher. The parts are clearly used, pulled components with new blacktop and markings. Technically they are "fake" parts because whatever pedigree were destroyed the with new markings, but they are fully functional, mostly.
Bill