Personally, I tend to think aging deer antler is overdone and too dark.
Take a look at many old measures in collections. Most that I've seen still look kinda white, 'specially when compared to what you find on the trade table at the fairs. Nothin' beats genuine use for that genuine patina. It really doesn't take too long neither. The oils from yer skin and residual dirt and grime take care of it just fine.
But if you want to cut back that just filed white gleam. I prefer a mug of this mornin's coffee. Dunk it in let it set a spell, fish it out. The feibing's can give ya a golden tone, but again, can easily be overdone. The trick is for the incised or recessed areas to appear slightly darker than the rest of the surface. That is where the 'dark' will accumulate.
I've noticed differences 'tween fresh antler and shed antler in its composition and color. One of the measures I made that won a ribbon at Dixon's was not 'aged' at all. While I was filing the shape, I noticed the color change from the typical bone white to a warm lavender-brown. This was a whitetail shed. I've noticed this color variation more-so in elk sheds.
Sometimes less is more.
Other's mileage may vary.
Regards