OK, so I ordered my case from Polycase and went to order the parts from Mouser and noticed that one part was unavailable. Mouser listed a similar part but being new at this I'm not sure if the similar part would be a proper replacement part. This was also the case with a different part when I looked at the BOM for the Express. Can I ASSUME (and we all know what means) that the similar parts that Mouser suggest are adequate replacement parts?