I have a GR3 12 ga and it is definitely not cross-bolted, but is ST and ejectors with blued frame. I also have a 425 12 ga, and the frame profile is identical to the GR3, and the wood is interchangeable between the two guns. I also have a 426E 20 ga, and it is ST with ejectors and a cross bolt. The 425 and the 426E have coin finished frames, and the 426E has pretty nice engraving, appears to be hand cut. All are 2-3/4" chambers. OP's gun appears to have 3" chambers.