Velly Interestink (Stolen famous TV show line). I haven't paid much attention to the Miroku '73 since I retired some years ago. However, seeing the picture of the action parts, there is no reason NOT to do it that way. Fit and function are the most important things.
Normally, the springs are set up so the "flat" runs very close to the side plates, to insure the springs stay where they belong. In this case, the flat runs next to the Carrier Block Arm and the "hook" runs next to the side plate. No reason why it shouldn't work. Also pretty obvious Miroku also decided to use Truck springs. I'd be guessing way too heavy.
Still, curious what Winchester says. Other than reducing the spring a mite, I'd not worry about it.