No, they dont offer DCC or not even know such thing. Again, these are all eateries frequent only by locals and the mainlanders.
More than one eateries actually told me, "we dont take Union Pay. It must be HKD." That is what I got from a local chain of mid-range banquet restaurants that is famous for their bargain period for breakfast that often has some really good dim sum combo at like 50% off. (稻香 - the Wanchai location above the Lee Garden is very good, not so much at other locations).
Even the very touristy Crystal Jade (翡翠拉麵小籠包) at IFC did not attempt DCC. They do have an attitude to mainlanders though as they mistook us being from mainland when assigning table. Had to talk to a manager to get things sorted. However, definitely not offered DCC option, nor automatically DCC our US-issued card.

I am talking about very Chinese-ish HKG eateries. None of them are Steakhouses - all of them are various Chinese foods - from big banquet restaurants for Dim Sum or Dinner, to the popular Tsui Wah chain. (翠華). My husband likes the Lamb chops there very much so we ate a few times at the 翠華 within 3 min walk from the HR TST - about as touristy location as you can get - NO DCC attempt whatsoever.

Not a single one attempted to DCC.
When I reiterated to the waitress / waiter when handing them my US-issued card I always asked them to bill in HKD. My brother told me not to worry more than one time that the restaurants will bill in HKD. We quite like the Cantonese banquet restaurant atop the Tin Hau MTR station. This restaurant is what I would term "Restaurant for the community" - it fills up around 7:30 every night with guests you know are from nearby. During the Mother's Day / Father's Day, Chinese Festivals, etc, the restaurant is full of extended families having a feast even though the prices generally go up 40% from normal days and all the "specials" were not offered. I was even scolded once by the older waitress when I asked to make sure it was billed in HKD - the 阿嬸 gave me a look, said LOUDLY, " If it is not HKD, what do you think?!" "WE DONT TAKE UNION PAY!"
I am just trying to tell you people, the eateries we go to, are VERY MUCH DIFFERENT from the restaurants you go to. Different preferences on the foods, and of course we dont much care for "atmosphere" - we only care for good foods at reasonable prices.
So there. It all depends on WHERE you go. Then in some places how you look and what language you speak, probably make a difference as well.

You can believe it or not I could not care less. We visited HKG 4 times in 2016, ate at enough restaurants whether only ourselves or with families, my US-issued CCs NEVER experience DCC. The only places are hotels where you do need to assert your choice and make sure they comply. They do comply even though the procedures often are not transparent and quite confusing.

Will report back on the upcoming trip during CNY period if I remember to drop by this thread after trip.

Now I would need to pay attention in Abu Dhabi and Dubai! Hardly any data on this thread or I have missed it.