SQL Server restore sequence from multiple full, diff and log backups
Personally, I like my backups to be timestamped something like MyDB-yyyymmddhhnn-Full.bak or MyDB-yyyymmddhhnn-Log.bak in the file name. I've never actually read the LSN from a backup file, neither have I read the LSN information from the system tables.

You can sort the files and pick out which ones you need quite easily.