I don't think the Chinese have perfected a method of counterfeiting lead that looks like uncirculated silver, so they have not focused on Washington Quarters. Most of the Chinese fakes look to be copies of Fine-Very Fine coins.
The greater issue in Washington Quarters are altered coins from other dates or added mint marks. There are 12 other dates in addition to the 32D & 32S which are near or over a $100 in MS: 34D, 35D, 35S, 36D, 36S, 37D, 37S, 38, 38S, 39S, 40D, 42S. Always check the mintmark area with a 10x/20x magnifier. The 32D and 32S can only be altered from 34s and 35s and plain 32s. The 32 quarters are really a unique one year sub-type with a full 3D medallic rendering of Washington. They were commemorative coins after all, so the care shows. The 34s & 35s have mushy details by comparison. The trickiest coin in the silver run in the lower MS grades (60-63) is the 36D. Have seen many four figure MS65/66s and a woefully high number of AU58s sliders masquerading as Mint State. A difficult coin to find in an affordable range of $500-$800.
Great overlooked series, my favorite by far, these quarters were the workhorses of the greatest generation. A complete uncirculated silver set is a thing of beauty. Of the 83 dates & mintmark combination, I am just missing one coin, the 1932D.