If I read the Vetter site correctly they were from the Vetter !
from his website:
What Lowers fit what:
Lowers were made specifically to fit the various popular motorcycles. Today, EBAY is the only source of Lowers. Type in Vetter and eventually, what you want will show up. You must be careful to buy the ones made for your year and brand. All Windjammer, Vindicator, and Kawasaki-by-Vetter fairings will accept any lowers made*.
According to Vetter Catalogs, the following lowers fit the following bikes:
Type 1: Fits pre 1979 Honda GL1000s and 1977 CB400F
Type 2: Honda CB750A; 1977-8 CB750K; Suzuki GS400X; GS550E; GS750E, L & Yamaha XS11, Special
Type 3: 1977-8 Honda CB750F; 1978-79 Kawasaki KZ650; Custom, KZ900, KZ1000, Std & LTD, MKII, 79 Suz GS 850 - 1000, EL
Type 4: Honda CB 550F, CB550K, CB650, Kaw KZ750; Yamaha XS360, 400, 500, 650, 650 Special, 750 and 750 Special
Type 5: 1975-6 Honda CB750F, 750K
Type 6: 1977-79 BMW/7
Type 9: Honda CX500, 78, 79. 80.
Type 10: CB750 K, L ,F, 1979-80
Windjammer 5
The Windjammer 5 was contoured slightly differently. Lowers made for previous Windjammers will not fit Windjammer 5 and vice versa
From "Windjammer V Lowers Mounting Instructions" dated 12-12-80:
Type 51: Honda GL1100
Type 52: Honda CB900 1980, CB750F, K, C 1979-1980
Type 53: Kawasaki KZ1000, MKII, ST
Type 54: Suzuki 550LX, 850GX, Yamaha XS1100
Type 55: Honda CX500, Custom, Deluxe
Type 56: Suzuki GS1100, GS750
*Only special Windjammer 5 Lowers fit the Windjammer 5. I suggest you stay away from this fairing if you will want Lowers.