Lowes sells the pactiv brand XPS board. I believe the 25PSI stuff is the Greenguard. The 25PSI strength is the ASTM type IV product class. Insulfoam has the R-tech IV product line. These are comparable to the Foamular 250 insulation.
Edit: Confirmed.
Here's the comparison sheet.
Lowes part # 304089 (1 inch), 304090 (2 inch)