What does a RNA Prep Values 260/280 value mean?

Sometimes this value can change due to changes in pH

When in doubt run a gel :)
A high 260/280 value generally does not mean anything is degraded, I always prefer running a gel to verify!

The 260//280 measures purity of DNA and RNA, 1.8-2 ratio means generally pure.
260/230 ratio measures the nucleic acid contamination, this value is often in the 2-2.2 range for RNA, a lower ratio may indicate contaminate of organic or carbohydrate origin.

A common culprit of high 260/280 values is dissolvents.
I notice if I dissolved my RNA in TE I tend to have a high 260/280 value
If you are using anything other then DEPC water for you dilutions for the spec you will have a high 260/280 value
If the cells where dissolved in another solvent/drug before the RNA prep a high 260/280 value is also seen.