I have an '89 Mark II Hi-Power (245PNxxxxx) with the staked front sight and top rib (ergo Mark II).

I've put a set of Hogue Kingwood grips on it, and I'm considering some 'mild' customization (sights, removing magazine safety, commander hammer). Is there any reason I should keep this pistol bone stock?

I'm in the queue for a Milt Sparks VMII holster, and I'm considering ordering a set of Nill grips as well. A BHP is rugged enough to be an EDC gun, and classy enough to be a BBQ gun, too.

I'd do it.

None of those enhancements diminish the gun's value at all and in fact if a reputable smith does them, they may add value.
Also, should you ever decide to sell it, the mag safety and hammer can be put back in.  I presume you want a dovetail cut for the front sight?
If so that would be the only permanent change - which by the way should include a refinish on the slide.

If you plan on doing it yourself, be aware that the hammer isn't a drop in part.
You'll likely wind up needing a new sear, and if you're going to do that you might as well look at an oversized thumb safety as well.

You sure about that?
I've never seen a MkII with anything except a front sight integral with the rib.

^^^THIS^^^

I sit corrected. The front sight is part of the rib.

I'm leaning toward a Novak dovetail front and rear with tritium inserts. Novak's website says they turn a sight installation around in about a week.

Turnaround time from one of the 'name' BHP smiths for hammer/sear/trigger seems to be pretty long. After I had the sights installed, I was considering a C&S hammer and sear and trigger work done by a local smith. Nashville has a LOT of good 1911 guys, but I'm looking for someone with some BHP chops.

KISS, for me I'd replace the sights, remove the MD and install a 2 coil trigger spring.  The hammer I'd leave alone and simply bob it by rounding it side to side and call it day.  In the end you should be very happy and spent considerably less.

To answer your question, yes, certainly, absolutely.  Your pistol is not likely to be a collectors item any time soon.

And if it were me.... I would throw in a trigger job.  Amazing what a good smith can do with a BHP trigger.  Oh, and since we're spending your money, stipple the front strap, back strap, and front of trigger guard.  Of course, then you'll need to refinish it which offers up a number of good options.  OK.. fine.. you get the idea.

Trigger job.. absolutely.  And some grip tape.  And you're going to love the Nil grips.  I much prefer them to anything including VZ's.