Could be. Maybe the people will know there.
As for the PC4300 RAM, there seems to have lots of standards out
there. Kingston produces it as a DDR SDRAM, not DDR2. See Kingston's report
DDR SDRAM has 184 pins, while DDR2 has 240 pins. Most other
companies produces it as DDR2 SDRAM.
There's some difference in how the manufacturers rate their RAM. No
idea why. To be sure, just check the website of the manufacturer.
TWINMOS and Kingston in this case, is very obvious in how they rate
it.