Chevy 5.3 oil capacity quandry..

That looks like the first gen 5.3. Only the numbers on the block will tell you different, see if it's an iron block or aluminum. As fas as the dipstick goes, well after several years of use the holder loves to break off at the bottom. Check around the base of it and see if it has been replaced. A sign is when u can see fresh scatch marks from someone trying to pull the old one off. They love to break at the base and then sometimes the bottom part stays in and other times it falls into the pan. It looks to me that that's the correct dipstick holder with that engine. My first gen 5.3 had the same Holder but a single piece dipstick. Now the top covering of the engine came fro the first gen 5.3, it's square where as the newer ones went to a round type. This does not appear to be a new 5.3 version to me just by looking at the pics. But I don't know where it came from, if it came from a junk yard then they tend to slap any missing parts on it just to sell it. If not then sometimes they are bad about what year or version the engine is. So point is to look at the numbers on the block and check them out.....you can't trust what the seller is telling u. Not that he may be deceiving you intentionally but he himself may just not know.
On edit.... Looking at the pic...that is for sur the older or first generation. It has an egr valve older style...... First gen motor had that exactly as pictured.