On a technicality it would seem that way but gate to source or gate to drain is the same based on over voltage on the gate
relative to any pin (FYI that's 20V). Its something that is variable in some circuits due to gate to source(or drain)
capacitance making a RF voltage divider. It may be more likely due to two things your at 75M and likely the
IRF510 tends to put out a bit more power there.
Its a bit of nastiness I got to see doing some class D and E amplifier work. Punch the gate oxide
and bad things happen. Most of the time I got to see that when the drain exceeded the drivers
ability to keep the gate below 20V due to Miller capacitance. Near instant poof. It tended to
happen more at 6.77mhz than at 13.55 or 27mhz.