I had a '78 Series I that had very severe checking and yellowing. I decided to go for a complete refinish and it ended up looking new. I really liked it. But, you can get it refinished with a tint added that approximates the aged look. But, I don't think you can adjust the current finish, it would need to be redone altogether.
Depending on the construction of the pickups, it could be that new ones might change the sound somewhat. I have a set of very early Series pickups in my Starfire that are rectangular shells with trapezoidal magnets inside. They have a resistance of under 1kohm, both of which contributes to the sound. They can be a bit noisy in certain environments, but the tone is so clear and deep that I would never swap them out. I'm not totally sure of what the state of Alembic pickup winding was in 1976, but your current pickups could be very unique sounding.
In any case, welcome! I can't wait to see some pix, I love these early basses!