No.
Based on its legs and hip anatomy Lucy would be unable to Knuckle walk. That is well established and not speculation. Which is
why the wrist features are considered vestigial remnants of a knuckle-walking ancestral phase.
Lucy has to walk on two legs and cannot knuckle walk. That is what I am calling bipedalism. The skeletal structures noted below, all found in bipedal humans and none in knuckle walking apes, establishes beyond doubt that Australopiths like Lucy walked upright in two legs habitually.
http://efossils.org/book/fossil-evidence-bipedalism
The oldest evidence for australopith bipedalism is found in the species
Australopithecus anamensis (4.2 to 3.9 Ma). Found in Kenya,
Au. anamensis most likely lived in a wooded savanna. Fossil evidence for this species includes
a preserved tibia that exhibits bipedal characteristics such as a right angle between the shaft and the proximal surface, and proximal articular condyles of nearly equal size. An abundance of the younger species
Au. afarensis (4 to 2.8 Ma) and
Australopithecus africanus (3 to 2 Ma) fossils also show clear signs of bipedalism, i
ncluding a bicondylar angle, an anteriorly placed foramen magnum, laterally flaring iliac blades, longer femoral necks and heads, and the presence of a lumbar curve. Though
Au. afarensis seems to have originated in Ethiopia and
Au. africanus is found only in South Africa, both of these species lived in open habitats, possibly wooded savanna areas near a lake8-10.
See detailed evidence and explanations of the bone features of Afarensis that shows habitual upright locomotion in two legs, explained in easy steps below,
https://elucy.org/wp-content/uploads/2016/02/lesson_step_by_step.pdf
Similarly the feet structure has human like arches that allows
only upright bipedal locomotion.
https://www.ncbi.nlm.nih.gov/pubmed/21311018
The transition to full-time terrestrial bipedality is a hallmark of human evolution.
A key correlate of human bipedalism is the development of longitudinal and transverse arches of the foot that provide a rigid propulsive lever and critical shock absorption during striding bipedal gait. Evidence for arches in the earliest well-known Australopithecus species, A. afarensis, has long been debated. A complete fourth metatarsal of A. afarensis was recently discovered at Hadar, Ethiopia. It exhibits torsion of the head relative to the base, a direct correlate of a transverse arch in humans. The orientation of the proximal and distal ends of the bone reflects a longitudinal arch. Further, the deep, flat base and tarsal facets imply that its midfoot had no ape-like midtarsal break.
These features show that the A. afarensis foot was functionally like that of modern humans and support the hypothesis that this species was a committed terrestrial biped.
Given so much skeletal evidence, the conclusion that Lucy walked upright habitually is inevitable.