What concerns me about the OP sig is the "y" starting with an upwards stroke, the "L" going down that low and the form of the "rr" which normally looks like a "M". The rest seems to fit to what I know from her sig. But her autograph always tends to be a little erratic, so maybe one mustn't be too much in love with details.
I don't know when she signed this, but toward the end of her life, Hedy Lamarr was legally blind. She died at age 87 in 2000. Any irregularities may be due to (a) her age, and (b) poor eye sight. Her autographs tended to get larger in her eighties.