Doug, I personally have not finished enough poplar to say, hopefully others will read this and have more experience with it, what I would say off hand, is pre-stain cannot hurt your project that I am aware of, it may be unnecessary, but it won't hurt it so all it will really affect is your pocket book, but as always the only real way to know is to try it and see if it makes a difference or not. If you are doing this on one of your tables, I think I would do that just so that I know how it affects the wood. Will be priceless to know for future project too