Actually, it is true. The overwhelming majority of Mosin-Nagants that were exported went through refurbishment, many have mismatched parts all over and many numbers were force matched. Sometimes with a stamped matching part the font is wrong, the Cyrillic prefix is missing or there is evidence of grinding, this tells you it was forced.
If you have a rifle, say a Tula check every marked part: barrel bands, band springs, nose cap, interrupter, extractor, cocking piece, etc, etc they will probably have an assortment of arsenal stamps because they often made no effort to match those parts.