There was a reason they were stamped with the War Assets mark. The C/i\ was a property mark, so if that was all the surplus item had, it could not be differentiated from stolen property. The WA indicated that it was sold as surplus. It is similar to the counterstruck broadarrows on British arms and the counterstruck broadarrows in a C on surplus Cdn arms.
By the late 40s, there was so much surplus out there the RCMP complained they could no longer tell stolen material from surplus. As a result, the C broadarrow was declared obsolete and no longer used. It was, however, mistakenly marked on some new material well into the 60s by manufacturers of some military goods, likely because the drawings for the items indicated how the items were to be marked and the drawings may not have been updated.
In the 1950s, there was a styalized arrow applied to military goods along with IS and a number. This was an inspector services mark, and not a property mark however.