[Jeff Ledger]

IMO, it's not.

/* BREADCRUMB */

.breadcrumb > ul {
	background:transparent url({vb:stylevar imgdir_misc}/navbit-home.png) {vb:stylevar left} top no-repeat;
	border:none;
}

.breadcrumb .navbit {
	float:{vb:stylevar left};
	background-image:url({vb:stylevar imgdir_misc}/navbit-arrow-{vb:stylevar right}.png);
	background-position:{vb:stylevar right} center;
	background-repeat:no-repeat;
	padding-{vb:stylevar right}:10px;
	padding-{vb:stylevar left}:3px;
}

.breadcrumb .navbit:first-child {
	padding-{vb:stylevar left}:0;
}

.breadcrumb .navbit.lastnavbit {
	background: transparent;
}

.breadcrumb .navbit.lastnavbit span {
	float:{vb:stylevar left};
	background: transparent;
	padding-{vb:stylevar right}:10px;
	padding-{vb:stylevar left}:3px;
}

.breadcrumb .navbit > a, .breadcrumb .lastnavbit > span {
	display:block;
	padding:2px 4px;
	float:{vb:stylevar left};
	background-color:transparent;
	border:1px solid transparent;
	-moz-border-radius:{vb:stylevar border_radius};
	-webkit-border-radius:{vb:stylevar border_radius};	
	border-radius:{vb:stylevar border_radius};	
}

.breadcrumb .navbit a:hover {
	border-color:{vb:stylevar lightweightbox_border.borderColor};
	background-color:{vb:stylevar lightweightbox_background.backgroundColor};
}

.breadcrumb .navbit a {
	text-decoration:none;
}

.breadcrumb .navbit a.popupctrl {
	background-image:url({vb:stylevar imgdir_misc}/navbit-arrow-{vb:stylevar right}.png);
	background-position:center center;
	padding:2px 6px;
	-moz-border-radius:3px;
	-webkit-border-radius:3px;
	border-radius:3px;
}

.breadcrumb .navbit a.popupctrl:hover {
	background-color:{vb:stylevar imodhilite_backgroundColor};
	color:{vb:stylevar linkhover_color};
}

.breadcrumb hr {
	display:none;
}

Here is the code for the breadcrumb in vbulletin-chrome.css, the default background-color is transparent and hard-code. So you must add additional css for this.