read the rules!
19. Original parts and components offered by the OFM as standard equipment, or as an option, for a specific model handgun on the IPSC approved handgun list are permitted, subject to the following:
19.1 Modifications to them, other than minor detailing (the removal of burrs and/or adjustments unavoidably required in order to fit replacement OFM parts or components, and/or identifying marks which add or remove negligible weight to/from magazines), are prohibited. Other prohibited modifications include those which facilitate faster reloading (e.g. flared, enlarged and/or add-on magwells, etc.), changing the original color and/or finish of a handgun, and/or adding stripes or other embellishments.
19.2 Base plates and/or any other devices which provide additional ammunition capacity (e.g. “+2” magazine extensions), are prohibited.
19.3 Sights may be trimmed, adjusted and/or have sight black applied.
20. Aftermarket parts, components and accessories are prohibited, except as follows:
20.1 Aftermarket magazines which match the external dimensions of standard magazines offered by the OFM for the approved handgun are permitted.
20.2 Aftermarket open sights (see Rule 5.1.3.1) are permitted, provided their installation and/or adjustment requires no alteration to the handgun.
20.3 Aftermarket grips which match the profile of the OFM standard for the approved handgun and/or the application of tape on grips (see Appendix F4) is permitted, however, rubber sleeves are prohibited.
So now based on the rules, if you could prove to me that the Hogue grips were the same profile as the Sig aluminium grips they would be legal. if not you could declare standard division and shot there. if however you declared production and you could not prove that they were the same profile as the OFM grips then you would get moved to open.