The ornamental design for a guidechock, as shown and described.
FIG. 1 is a front perspective view of the guide chock.
FIG. 2 is a top plan view thereof.
FIG. 3 is a bottom plan view thereof.
FIG. 4 is front elevation view thereof.
FIG. 5 is a rear elevation view thereof.
FIG. 6 is a left side elevation view thereof.
FIG. 7 is a right side elevation view thereof; and,
FIG. 8 is a rear bottom perspective view thereof.
The surfaces are lightly lined for contour which forms no part of the claimed design. The dash-dash lining indicates disclaimed portions of the ornamental design. The dash-dot-dash linking demarks a disclaimed region of the design and no claim is made to the portion therein. No claim is made to portions of the design which are not shown.