I have two Rics. The newer 2009 4003 came stock with 2 hi-gains, and the vintage push/pull switch.
With the switch pushed in, the .0047 bridge pup cap is bypassed. Since both pups are sending out similar signals via parallel wiring, but sensing different parts of the strings, you get that Fender Jazz-like growl due to some phase canceling, also referred to as combing. But still a very Ric-ish growl. The hi-gains are great pups, just right for grindy, growly tones that can cut through the mix.
With the switch pulled out, the .0047 cap is now in-line with the bridge pup, acting as a hi-pass filter, cutting out approx 150hz and lower. The cap also shifts the phase of the bridge pup 90 degrees or so, eliminating any combing, so you get the pure effect of both pups. You can actually get more low fundamental out the neck pup if you dial down the bridge pup slightly. To test this, switch the toggle from both to neck and see if you hear a difference. If not, you have the bridge dialed down too far. Dial the bridge up a smidge until you begin to hear a slight difference when toggling between both and neck. That is close to the true vintage Ric sound.
I outfitted my other Ric, a 1993 4003s, with Ric re-issue pups, 11.7K horseshoe in the bridge; and 7.4K scatterwound toaster in the neck, routed to be in the older 1/2" position from the fretboard. The neck toaster has a different tonal quality than the hi-gain. I use this bass almost exclusively with the cap in. To overcome the output difference in pups, I just dial the bridge down further than on my other one. Now I've got about as close to that true vintage Ric tone as you can get without buying a vintage Ric.
But nothing will sound like a true vintage Ric. Even contemporary model have differences in tone. New maple is different from 1960's maple, and if yours had a neck with the shedua stripe, that alters tonal quality as well. Bridge metal was probably different, and pup winding have changed throughout the years as mentioned, along with different magnets, etc. Tone pots were once 500K, etc, etc, etc.