Here is a hard to find pattern from McCall's Evening Elegance collection - Pattern #3853 Gown (Prom or Wedding Dress with separate Top and Skirt in sizes 6, 8, 10 and 12
MISSES’ LINED TOPS AND SKIRTS: Close fitting lined tops A thru D have boning, front detail variations and back zipper closure; top A and B has front lacing variations; top B has shoulder straps; top D has neck strap; top C and D have frog closure; skirt E and F have back zipper closure, front seaming and waistband; skirt E has flat waist; skirt F has attached overskirt gathered into waistband.
Size 6 ~ Bust 30 1/2" Waist 23" Hip 32 1/2"
Size 8 ~ Bust 31 1/2" Waist 24" Hip 33 1/2"
Size 10 ~ Bust 32 1/2" Waist 25" Hip 34 1/2"
Size 12 ~ Bust 34" Waist 26 1/2" Hip 36"
This is an UNCUT pattern with the instructions and pattern still factory folded. Envelope shows some shelf wear that doesn't effect the pattern.