Generally, they do appear to be an in-kind possible match.
According to MacTracker, your Mini (mid-2011) can use more RAM...
Maximum Memory | 16 GB (Actual) 8 GB (Apple) |
Memory Slots | 2 - 204-pin PC-10600 (1333 MHz) DDR3 SO-DIMM |
...while the RAM specs for the iMac 21.5" (mid-2011) look similar...
Maximum Memory | 32 GB (Actual) 16 GB (Apple) |
Memory Slots | 4 - 204-pin PC3-10600 (1333 MHz) DDR3 SO-DIMM |
mini: http://eshop.macsales.com/shop/mac-mini/
imac: http://eshop.macsales.com/shop/apple/memory/iMac
By the small print, in this example (2x4GB= 8GB//2x8GB=16GB) these should match:
http://eshop.macsales.com/item/Other%20World%20Computing/1333DDR3S08S/
http://eshop.macsales.com/item/Other%20World%20Computing/1333DDR3S16P/
{for iMac 32GB}
http://eshop.macsales.com/item/Other%20World%20Computing/1333DDR3S32S/
By clicking on the section where the RAM details are, you can see if they
are suggested by their experts, as a likely & guaranteed upgrade/match.
And most recommendations are for upgrades in matched pairs of RAM.
Good luck & happy computing! 🙂
{PS: while I don't use OWC or macsales products, they offer quality examples}