If they were the same exact model and code I would say yest but they are not. Even if the ASA5510 has the same code as the 505 they are not the same hardware platform. Take under consideration the physical interfaces, and any other configuration on the 505 to cary onto the 5510.
I would configure the ASA 5510 offline from scratch following the IP interface configuration, rules, nating etc.. specs from the 505.. load both PIXs using ASDM if nessesary to make the configuration easier on the new one, once fully configured come up with an implementation plan to swap the firewalls.
Jorge Rodriguez