I just came across a pair of C51 Apollos with LE14, 175DLH and with LX10 crossover and I can't seem to find any info about this combination.

They look like factory built but the only C51 I know always had a "15 and a slant plate lens on them.

Take a look: http://www.marktplaats.nl/a/audio-tv...c-51-rare.html