whats the resale value on a SM465-205 adapter?

and do you need one of these adapters to replace a 208 with a 205 behind a 465? or does it reuse the adapter?

thanks

They are pretty common, usually you can get the whole SM465/adapter/NP205 for $150 or less. You'd need the adapter to put a 205 in place of a 208, but you'd also need the SM465 with the 10 splline output.