There are two primary varieties of this stamp. One stamp has the F denomination which follows the letter designations used by previous rate change stamps. The other has the 29 denomination.

The F stamp comes in 4 varieties, of which two will take a small amount of time to identify them. The sheet stamp, with perforations on all 4 sides is Scott #2517. The coil stamp with perforations on the right and left sides only is Scott #2518. Scott #2519 and #2520 are the booklet stamps that take a little work. Scott #2519 uses a brighter yellow background and the grenn leaf is printed in a darker green color. Scott #2520 uses a pale yellow background color and a bright green color for the leaf. If you see two stamps side by side, its very easy to spot the differences.

The 29 denominated stamp comes in five varieties. Again, only two of them take a little effort. Scott #2524 is the perf 11 sheet stamp. Scott #2524A is the perf 13 by 12.75 sheet stamp. Scott #2524A is more scarce and a plate block of #2524A catalogs $50. When buying mint postage, keep your eyes open and you might pick up #2524A instead. There are two coil issues. Scott #2525 is rouletted (it has tiny slits between the stamps). Scott #2526 is perf 10. And lastly, Scott #2527 is the booklet stamp.

In summary:

 

Scott # Design Format Perf Notes
2517 F Sheet 13
2518 F Coil 10
2519 F Booklet 11 Bright yellow background and dark green leaves
2520 F Booklet 11 Pale yellow background and bright green leaves
2524 29 Sheet 11
2524A 29 Sheet 13 by 12.75 More scarce than #2524, especially the plate block
2525 29 Coil Rouletted Small slits separate the stamps, not perforations
2526 29 Coil 10
2527 29 Booklet 11