[cflsystems]

<td height="35" align="center" class="HeadText">
{if $config.Company.company_phone}{$lng.lbl_phone_1_title}: {$config.Company.company_phone}{/if}{if $config.Company.company_phone_2}&nbsp;&nbsp;&nbsp;{$lng.lbl_phone_2_title}: {$config.Company.company_phone_2}{/if}&nbsp;&nbsp;</td>
</tr>

You can change the class HeadText in your css file or you can do this

<td height="35" align="center" class="HeadText">
{if $config.Company.company_phone}<b>{$lng.lbl_phone_1_title}: {$config.Company.company_phone}</b>{/if}{if $config.Company.company_phone_2}&nbsp;&nbsp;&nbsp;<b>{$lng.lbl_phone_2_title}: {$config.Company.company_phone_2}</b>{/if}&nbsp;&nbsp;</td>
</tr>