Yes. If they use the same protocol, hopefully version 2. Regarding the generation of the private/public keys for passwordless authentication, take in mind that ssh-keygen from OpenSSH provides the option -e for compatibility:
Code:
-e This option will read a private or public OpenSSH key file and print the key in RFC
4716 SSH Public Key File Format to stdout. This option allows exporting keys for use
by several commercial SSH implementations.
However you have to follow specifications from each specific version of ssh to install keys. The method may differ between commercial SSH and OpenSSH, but it should be as easy as reading
man ssh on each server.