Hi,
For OSPF reference bw, I don't know any CLI command to check. For this parameter (And a lot of other global parameters), you have not option but to TRUST what has been configured on the router.
Even if we have some commands like "show ospf overview" which provides the reference bw. What additional value is it adding on top of the config? Fairely speaking, we are NOT expecting any difference between what has been configured and what is applied
We all know how to do the math here: cost = reference BW / BW
You can do "show ospf interface extensive" and verify the cost on the link