$3,500 sound like a reasonable estimate for this? I'm sure it's 10x the actual cost of some 5200 and labor to drop the keel, torque the bolts and clean up the joint when finished, but backs against the wall, I don't have the time or equipment to figure this one out on my own. This is Chicago where everything is more expensive as well.
Seems like a lot to me. Ask Sailnet member CharlieCobra - he should know the answer.
Why can't you have it blocked, loosen the bolts yourself, have them raise the boat a little with the keel supported, re-block, work the seam between keel and bolt to ensure it separates, raise the boat again to separate from the keel and reblock, work on the joint to create a good matching seal between keel and boat, add 5200, re-bed, tighten all bolts, set and relaunch?
Or, here is a novel idea: have boat blocked an extra foot high, with some kind of removable blocking or jacked blocking under the keel, loosen the bolts and work the seal between keel and hull, drop the keel in place with side supports, work the keel-hull joint, then have the boat dropped down to the dropped keel level, or if you are able, jack the keel back up into the boat.