I have a habit of buying old bowling balls to help my game. Really to save money from buying a new ball. Some old bowling balls I seen on the lanes still hook. I'm wondering if old bowling balls can hook as much as new bowling  balls can?

New balls tend to be too strong on house shot anyway especially if you have learned how to create leverage and revs.  Now for heavy sport then yeah the new stuff is more needed.

No.
New covers are just stronger, more reactive, more porous, and more responsive to friction.  Just the reality of technology and evolution, as oils, additives, volumes, and patterns also evolve.

BUT... you don't always need 'more', and using a ball too strong, can have negative effects on motion both left to right and front to back, resulting in less energy transfer, poor shape, and bad pin carry.

Sometimes less is more, otherwise everyone would just throw the strongest ball possible.

Honestly, I have probably have the largest list of old school hook monsters with some new ones mixed in.

Careful with that assumption on here lol.  Some real ball hos up in here.  I am barely in triple digits and think I am more towards the low end to some on here.  Speaking of old stuff finally scored me a Dyno-thane Vendetta Black.  Can't wait to throw that one as should be a house shot killer around here.  Have plenty of new stuff sitting in boxes un-drilled but its gems like this that get me excited.

Here is my 2 cents on this.

Can older balls (15 or more years old) hook as much as newer stuff?  Yes.  But relative to lane conditions.  An older ball on a 32-34 foot pattern will hook as much as a newer ball on a 38-42 foot pattern.

The only ball I can think of that would hook as much as modern balls is the Visionary AMB Particle.  But that is because out of the box surface was 320 wet sand and a heavy load particle with a differential of .062.  Higher end balls from 2000 are no where as strong as a modern high end ball.  I have a Hammer 3D Pearl still in great condition was considered one of the most skid flip balls of its time.  At 20 mph and 540 rpms; I still had to play inside 3rd arrow and deeper for this ball to really shine.  NOW......at 18 mph and 500+ rpms; I can play in the track area.  I am 2 mph slower and yet now close to 2 full arrows tighter on the lane. 

Another thing to consider; in the late 90s and maybe into the early 2000s, the underlying grit beneath the polish was typically 400-600 grit sandpaper and yet the balls would still push down the lane a pretty decent amount.  If you were to take a high end ball such as a UFO, Gravity Evolve, or Redemption Solid and put it at that same surface; you may get lucky to get the ball 25 - 30 feet down the lane unless you are pretty speed dominate.  Most of the new high end balls seem to have 2000 abralon/siaair on it whether it is 500/2000 or a true 2000. 

Yet another consideration.......All of the remakes such as the Triton Elite Solid, Columbia Beast, Limited Edition V2 Solid, and others have updated covers.  The only thing that is identical to the original release is the core.  But even cores get slightly modified.  All of the updated versions have stronger covers to handle the current lane conditions.