Maybe J for Japan, since we bought in Japan?
In 2016 we got a Cisco C891F-K9 V01 from the USA.
In 2017 we ordered the same, a Cisco C891F-K9 in Japan and we received a C891FJ-K9 V02 instead.
Why? What does the V01 or V02 mean? Is it a version or release code?
Most important: is there no or no significant difference in functionality and capacity?
A proper answer from Cisco would be good after 1 year latency on your question ....
Especially when you want to advise a customer for appropriate ethernet-only (non-wireless) type.
Similar question was there before https://supportforums.cisco.com/discussion/12428816/c891f-k9-vs-c891-k9