Hmm...... not so clear it seems?
01 belt only have the locking mechanism in the LAP belt.
Was that changed in 02 with locking also in the SHOULDER belt??
I read some other place here that the new C6 Z06 had positive locking in both places, if first pulled all the way out.
Back to square one, could you install the lap belt mechanism/roller in the shoulder belt position and another thing, can you take out the belt only from the mechanism roller and reinstall a lap mechanism in its place and simply reinstal the belt cord in the roller
I get the impresion that best option might be to go 6 point and a harnes right away!