Is it tacky to note awards on a conference poster?
If the goal is to have an engaging poster, do you want to engage those who are also researching your topic/field or engage anyone who would be interested in a paper that received accolades, regardless of the topic? The latter does not necessarily result in more exchange in ideas that could further the state of knowledge on your topic, which is what poster presentations are designed to do.

My advice is to design a poster that is engaging through its use of design and content, rather than adding blurbs about its praise. You will engage the right audience, giving you opportunity to talk about the paper with people who might actually read it and use it for their work. A boring poster won't engage a wide audience, even if you include information about it's accolades.