. . but oyster sauce should be available in just about any market that has some Chinese or Philippine stuff. It's one of the most common sauces. It's also used in Vietnam and Thailand for dishes "in the Chinese style".
I haven't tried grilling asparagus yet myself, 'cause I haven't been real impressed with it elsewhere. I may give it a try this summer.
PLU numbers are uniform across the U.S., but there are some that aren't real precise, such as "green avocado". To avoid excessive rigidity there are numbers assigned to many fruits and vegetables as "retailer assigned", but most used around here are the standard ones because the little oval stickers are applied by the distributors, not the store.
Here are links:
PLU numbers Alphabetical:
http://www.innvista..../plucodes_abc.htm
PLU numbers Numeric:
http://www.innvista..../plucodes_123.htm