Thanks Koda
Well looking at the board layout and manual for the P5E3 Pro it does look practically the same, the only difference is the P5E3 Pro has "Express Gate", P5E3 and P5E3 Pro both have 12VATX connectors instead of EPS12V connectors like other P5E based boards and they both have the same number and position of PCI and PCI-E slots.
P5E3 Product Page
P5E3 Pro
John