Leaky capacitors need replacement?

All is well except the bias won't zero down and there seems to be a low hum over speakers at idle which I don't think was there before.

Those caps may not be the only ones that were bad. But your tubes can cause both hum and bias problems- have they been tested?

There's nothing weird or crazy about these amps- they can be easily repaired by anyone competent with tube circuits.

Those are polarized capacitors and should be replaced with the same type and value. Film won't fit! Non-polars won't fit either.

@shawn3997

Just a FWIW, if those caps are used in an application where they are seeing a higher voltage closer to their rated voltage (in the photo it looks like its in a DC Blocker to me, but who knows), I can tell you from experience that those Illinois caps can do that well short of the time you expect of them. Switching to a Nichicon will assure longer life. As @clio09  recommends, replace them with the same value and voltage.

If this is a DC blocker, I question whether the lowest impedance capacitor is the best choice. That means more high frequency noise is passed through. Thoughts?

No- it doesn't work that way. Actually though if this is a DC Blocker as it appears the voltage only need be 16 volts not 350.

@clio09 is associated with service of these amps. Tony, can you confirm that this is the DC Blocker circuit?

Are you saying to replace the electrolytics with new electrolytics or use something else? These are right off the AC mains between the IEC plug and the rest of the amp.

These parts are being used in the DC Blocker inside the amp.

They should be replaced with the same value and voltage. @timlub has mentioned some nice quality parts to replace yours, which have a tendency to do this long before their time.