Ask HN: A PICMG 1.3 SBC as a 1.0 replacement?

I have an old mainframe with a PICMG 1.0 card, but would like to use a 1.3 with a VT-d CPU and chipset in order to run a modern Linux on the SBC and pass through a PCI card to a VM running OS/2. While they have the same form factor, I am uncertain if a 1.3 can be substituted for a 1.0 SBC. The loss of ISA bus support with 1.3 is fine.