For all parts from 1997 (USA) or 1996 (Europe) and up, there are no changes mechanically. The only changes are cosmetic.
So that tasty new Micron that lists for 1998 through 2003 will fit your 2007 model just fine.
Some pre 1997(USA) YZF600r parts WILL fit the newer bikes. Engine internals in many cases are the same, exhaust, rear rims/sprockets are the same to name a few. Front wheels and forks are different and won't fit without major work. Airbox & carbs are also different.
Some brake components from early-model R6's will fit, as well as some FZR600 and YZF1000 parts.
When in doubt compare the microfiche part numbers. If the part numbers match perfectly, it's a direct replacement. If the first grouping is different then the parts are most likely NOT interchangeable. When dealing with rims or plastics, the last grouping will denote the colour/paint scheme.
Another great resource for common consumable parts is an aftermarket parts manual. Check the listing for the brake pads of choice, and then see what other bikes the same part number services. Voila!! You've just expanded your ebay part search window.