I don't think standard Rattata has loot. Here's what makes me think this way.
 
	 
 
	I started to use covet on Meowth and Rattata during the day in Opal Ward.
 
	-- I've gotten 2 or so quickclaws (that's at a the reduced spawn rate compared to ratatta)
 
	 
 
	-- Rattata has yielded no berries whatsoever. Despite me running into tons of rattata.
 
	 
 
	According to Bulba. US/UM  A. Ratatta has carried pecha berries, while the standard rattata hasn't carried loot since HGSS.
 
	~I also think A. Rattata doesn't  spawn in Opal ward. (I've looked in all times Morn./Day/Night
 
	 
 
	Update:
 
	I just did a 100~ encounters with Rattata in Opal ward and got 0 pecha berries. 
 
	Meowth on the other hand gave me 7 quick claws @ 60~ encounters
 
	 
 
	Will let you know if more held items are wrong. So far so good, I just tried Grimer and got black sludge.