Late 50s the 4000 Bass had a 4 degree PH angle. This continued except in the early through late/mid 60s when the neck thickness was slimmed down leaving vey little wood at the area below the top nut. This weakened the neck causing the PH to pull upward decreasing the PH angle over a period of time to almost flat with the fingerboard. This is why Maccas Bass has a Zero Fret with a tall top nut behind it. When his Bass came through the shop in the summer of 1976, we replaced the HS pickup and pickguard. He left very specific instructions not to change or adjust the neck or string height, he likes it on the high side. We had to replace the nut behind the Zero fret because someone in the final assembly dept. stole it, drilled a hole in it and put it on their key chain.
So to answer this question: From 1957 through the late 1960s there was a 4 degree PH angle, then the neck shape was changed along with the PH angle to 3 degrees.
This continued on through the 1970s, after that I have no knowledge but a simple guess would be back to 4 or 5 degrees.