Final answer:
The enforceability of the oral agreement for additional items in a truck sale might be recognized by the courts if Alvin can prove the agreement, although the original contract stipulates modifications need to be in writing. The agreement depends on various factors, including the conduct of the parties and principles of equity.
Step-by-step explanation:
The enforceability of the oral agreement between Lucky and Alvin can be complex due to the existence of the original written contract, which states that modifications must be made through a signed writing. However, contract law generally recognizes that an oral agreement to modify a contract can still be valid under certain circumstances, despite such a clause.
In practice, issues may arise if one party, such as Lucky, decides not to honor the oral modification. If Alvin can prove that the oral agreement was reached, perhaps through witnesses or admission by Lucky, the courts might enforce it, especially if Alvin has already acted in reliance on the agreement (e.g., by paying the extra $100). On the other hand, the presence of the written clause could complicate matters and Lucky may argue that any modification needs to adhere strictly to the 'signed writing' requirement.
If a dispute reaches court, the outcome would depend on the specific laws and facts of the case, including considerations of the earlier agreement, subsequent conduct, and principles of fairness and equity. Alvin may face challenges, but he is not necessarily without legal recourse.