This is results for some of our drives:

1 2 3 4 5 6 7 8 9 10
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1 C:\ RAZVAN 200 573159436 255 16390 FAT 200 | Local
1 D:\ UTILE 200 0 255 16390 FAT 200 | MSNetWare
1 E:\ CATALINA 200 0 255 16390 FAT 200 | MSNetWare
1 F:\ SYS 200 0 12 0 NWCOMPA 200 | Novell 3.11

1 = lresult
2 = lcpath
3 = lcvolbuff
4 = lnvbuffsize
5 = lnserialno
6 = lncomplen
7 = lnsysflags
8 = lcsysbuff
9 = lnsbuffsize
10 = drive type

As you can see "lnserialno" is returned only for local drive.
Can you get Serial Number for net drives?