IMO, no, not unless you drill a hole in the thermostat.
With the bypass blocked and the thermostat closed, there is almost no water circulation. But there is still the usual amount of heat put into the water around the exhaust valves, so the coolant there can get a lot hotter than the thermostat setting, even boil, before the water at the thermostat gets hot enough to open it. Then when the thermostat finally does open, there is a rush of still-cold water (potentially below freezing in cold weather) into the near-boiling (or even higher) cast iron cylinder head. The sudden thermal shock can result in cracks.
The GTS104 type thermostat actually became the standard thermostat later on, and is listed as a factory-approved supercession for the earlier type. The thermostat housing was slightly redesigned, mostly I suspect to make it easier to cast, but the new casting did have a slightly smaller bypass passage.
I've experimented several times with my own cars; I found no real-world difference in cooling between fully blocked and fully open.
My current cooling system is not stock (mostly electric fan and an overflow bottle), but I have no cooling issues whatsoever even in 115F ambient temps, with the bypass fully open. (The driver overheats before the car does, at 115F I start looking for someplace cool to wait for the sun to go down.)